Posture in the brain

Our understanding of the neural basis of motor control originates in studies of eye, hand, and arm movements in primates. Mimica et al. investigated neuronal representations of body postures in the posterior parietal and frontal motor cortices with three-dimensional tracking of freely moving rodents (see the Perspective by Chen). Both brain regions represented posture rather than movements and self-motion. Decoding the activity of neurons in the two regions accurately predicted an animal's posture.

Abstract

Animals constantly update their body posture to meet behavioral demands, but little is known about the neural signals on which this depends. We therefore tracked freely foraging rats in three dimensions while recording from the posterior parietal cortex (PPC) and the frontal motor cortex (M2), areas critical for movement planning and navigation. Both regions showed strong tuning to posture of the head, neck, and back, but signals for movement were much less dominant. Head and back representations were organized topographically across the PPC and M2, and more neurons represented postures that occurred less often. Simultaneous recordings across areas were sufficiently robust to decode ongoing behavior and showed that spiking in the PPC tended to precede that in M2. Both the PPC and M2 strongly represent posture by using a spatially organized, energetically efficient population code.